An eye-mountable device may be configured to monitor health-related information based on at least one analyte detected from an eye of a user wearing the eye-mountable device. Such an eye-mountable device may include a sensor apparatus configured to detect at least one analyte (e.g., glucose). For example, the eye-mountable device may be in the form of a contact lens that includes a sensor apparatus configured to detect the at least one analyte. The sensor apparatus may monitor health-related information of a user of the eye-mountable device, such as glucose level of the user. Further, the sensor apparatus may monitor various other types of health-related information.